A federal panel has given a weak endorsement to two expensive new meningitis shots, declining to recommend the vaccines for all teens and leaving the decision to parents and doctors.

At a meeting Wednesday in Atlanta, the panel approved a half-measure that says older teens and may get the shots—if they and their parents want to take that step.

That statement is enough to greenlight insurance coverage of the new shots.

The vaccine targets bacteria that can cause dangerous meningitis or . Such illnesses are extremely rare, but have caused recent outbreaks at colleges.

Students already get another that protects against more common strains.

The new shots are expensive and their long-term effectiveness is unknown.

More information: CDC: www.cdc.gov/vaccines/acip/